⚠️ Apply VAS

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description explicitly warns about charging money and irreversibility, aligning with destructiveHint=true. It also explains the response content (service data, charged amount) and idempotency key behavior. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is relatively short (6 sentences) and front-loads purpose, warnings, and alternatives. It could trim redundant phrasing but is mostly efficient and well-structured.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (5 params, no output schema), the description covers all essential aspects: purpose, money impact, deprecation, alternatives, prerequisites, error handling, and parameter clarifications. The response format is briefly described. This is complete for agent execution.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 100% schema coverage, baseline is 3. Description adds valuable context: examples for vas_id, explanation of dryRun and idempotencyKey defaults and behavior, and the prerequisite for vas_id values. This significantly surpasses the baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool applies a single VAS to a listing, with explicit verb 'Applies' and resource 'listing'. It distinguishes from siblings by noting deprecation and pointing to alternatives (items_apply_vas, items_put_item_vas_package_v2).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides explicit usage context: use for single VAS, but prefer alternatives for multiple services. Includes prerequisite call to items_post_vas_prices, user confirmation requirement, and post-error recheck note. This guides the agent on when and how to use.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.